Flooding on State Highway 16 in Araparera, Kaipara. Photo / Michael Craig
MetService has upgraded Tuesday’s heavy rain warning for Northland to red - a first for the region and reserved for only the most extreme weather events.
Locals are being told to prepare as Tuesday promises to deliver strong winds, torrential rain, and severe thunderstorms.
Waka Kotahi Transport Agency has also announced the toll on the Northern Gateway has been paused from today until the state of emergency in Auckland is lifted to help provide an alternative route to a flooded State Highway 16.
Northland Civil Defence Controller Graeme MacDonald said the Red Warning is only issued for the most impactful events and today’s is the first time one has been issued for Northland.
With the newly-forecast heavy rain coming on top of the constant heavy rain battering the region, MacDonald said, streams and rivers may rise rapidly and become dangerous.
“Surface flooding, slips and flood water are likely to close roads and disrupt travel. Flooding of low-lying areas is also possible.”
MacDonald said MetService has forecasted between 100 to 140mm of rain in the north and east of the region for the 24 hours from 4am tomorrow to 4am Wednesday.
However, he warned localised areas may receive as much as 140 to 220mm over that same period.
“Peak rates of 10 to 20mm/h are expected, but again, localised areas could see 25 to 40mm/h from thunderstorms.”
MetService expects the rain to start in the north, with potential impacts being seen across the region by Tuesday afternoon.
There is also a Severe Thunderstorm watch from 4am tomorrow until 4am Wednesday and a Strong Wind watch from 10am tomorrow to 2am Wednesday.
MacDonald said the Northland Civil defence team is currently monitoring the situation in close contact with MetService and the Northland Regional Council Hydrology team.
“This afternoon we met with all three of Northland’s district councils, local emergency services and other key stakeholders and we are all preparing to respond if need be.”
He said the key message with the new warning was for Northlanders to stay prepared.
“Have a plan in case you need to evacuate, keep up to date with the lasted information and weather conditions, and most importantly avoid any non-essential travel tomorrow and potentially Wednesday morning - if you must drive, please drive to the conditions and keep an eye out for hazards.”
Floodwaters have submerged parts of State Highway 16 in Araparera, near the Kaipara Harbour.
The Brynderwyn Hills are still closed from the SH12 intersection to Waipū. Waka Kotahi NZ Transport Agency said motorists should expect delays as they detour via Waipū and Mangawhai.
“With additional slips occurring overnight and more wet weather forecast over the coming days, heavy traffic must use SH12 and SH14 as a detour while lighter vehicles will be able to use a sign-posted local road detour.”
Traffic will be detoured until further investigations can be completed.
Trailer trucks and large trucks are advised to use SH12 and then SH14. Trucks using SH16 coming north are getting stuck on the corner at Lane Cove, Waipū, Civil Defence has said.
SH1 between Port Marsden Highway, SH15, and Marsden Point Rd has reopened after the deteriorated road surface was repaired.
Punaruku near Ōakura flooded and became impassable, locals reported. However, waters have begun to subside and 4WD vehicles are able to travel through.
Motorists have been given a reliable alternative to SH16 which is being affected by flooding and the Hibiscus Coast Highway on-ramp which is closed due to damage, Waka Kotahi said.
“People are still being urged to stay home if possible. If travel is essential, ensure you exercise extreme caution and drive to the conditions. Be prepared for some road surfaces to be rough where rain has stripped top layers of the seal and watch for flooding and other debris on the road.”
Flooding between West Coast Road and Kahikatea Flat Road has caused this section of SH16 to close. There is a local road detour available, but further flooding could affect this route. SH1 remains a more reliable route at this stage.
MetService meteorologist John Law said there had been huge amounts of rainfall across Northland overnight.
“Kaitāia received 35mm of rainfall in less than an hour in the early parts of this morning. Since then, there has been 76mm of rainfall in Kaitāia.”
From midday Thursday through to 11am Monday Kaikohe has received 174.8mm, Kaitāia has received 139.4mm and Kerikeri 129mm.
Law said in the past 24 hours up to 10am, Dargaville had received about 30mm of rain - still a “sizeable amount” - and around 17mm of rain had fallen in Whangārei in the 24 hours up to 10am.